Modifying and Rebuilding Android Kernel and Root Filesystem Modifying and Rebuilding Android Kernel and Root Filesystem 1 Document History Date Version Change Description 02/27/2012 1.0 Initial version 04/16/2012 1.1 Integrating review changes 12/06/2012 1.2 Updated to support AADK 1.2 Copyright 2012 Digi International Page 2/13 V1.2 Modifying and re-building Android Kernel and rootfs Modifying and Rebuilding Android Kernel and Root Filesystem 2 Table of Contents 1 Document History ....................................................................................................... 2 2 Table of Contents ........................................................................................................ 3 3 Introduction ................................................................................................................. 4 3.1 Problem Solved ................................................................................................... 4 3.2 Audience ............................................................................................................. 4 3.3 Assumptions ........................................................................................................ 4 3.4 Scope ................................................................................................................... 4 3.5 Theory of Operation ............................................................................................ 4 4 Basics .......................................................................................................................... 4 4.1 Preparing the system and installing tools ........................................................... 4 4.2 Configuring the environment .............................................................................. 5 4.3 Re-Configuring Android Kernel ......................................................................... 7 4.4 Modifying Root filesystem ................................................................................. 9 4.5 Re-building Android Kernel and rootfs ............................................................ 10 4.6 Checking generated Android Kernel and rootfs images ................................... 11 4.7 Deploying new images on to the target............................................................. 12 4.7.1 FLASH BOOTING (TFTP server required) ............................................. 12 4.7.2 NFS BOOTING (NFS server required) .................................................... 12 4.8 Debugging new system ..................................................................................... 13 5 Conclusion ................................................................................................................ 13 6 Appendix ................................................................................................................... 13 6.1 Glossary of terms .............................................................................................. 13 Copyright 2012 Digi International Page 3/13 V1.2 Modifying and re-building Android Kernel and rootfs Modifying and Rebuilding Android Kernel and Root Filesystem 3 Introduction Customers who need to add additional device support, drivers and features to Android will have to rebuild Android Kernel and rootfs. 3.1 Problem Solved This document will show how to customize and rebuild Android kernel and root filesystem images 3.2 Audience Customers using Digi embedded Android SDK on ccwmx51 and ccwmx53 based modules, who need to add additional device drivers our other functionality and/or customize root filesystem to contain their own applications and configurations. 3.3 Assumptions This document was created in reference to Android SDK v1.2.0 3.4 Scope Extract and install sources and toolchain Configure and customize Android kernel and root filesystem Rebuild Load and run new images on target 4 Basics The copy of the source code and toolchain required to rebuild Android kernel and root filesystem images is located on the Android SDK DVD in the tar file. Following the procedure below will require having an installation of Linux distribution on a host machine. Rebuilding Android Kernel and rootfs under Windows is currently not possible. As we only supply Linux based toolchain. Kubundu 10.x installed from Digi Embedded Linux Live DVD was used as an example to demonstrate the process below. 4.1 Preparing the system and installing tools The copy of the source code and toolchain required to rebuild Android kernel and rootfs images is located on the Android SDK DVD in the tar file. Extract the code from a tarball included in the DVD (/src folder). Once uncompressed, the whole project occupies nearly 3.5 GBs. cd ${HOME} tar xvfj /<path to tarfile on DVD>/aadk-<version>.tar.bz2 Copyright 2012 Digi International Page 4/13 V1.2 Modifying and re-building Android Kernel and rootfs Modifying and Rebuilding Android Kernel and Root Filesystem Here is an example showing my steps on a host machine. I am using a Kubuntu Linux that comes with Digi Embedded Linux kit. Digi Android SDK DVD v1.2 is mounted under /media/AADK: leonidm@ubuntu:~$ ls -la /media/AADK/sources/aadk-1.2.0.tar.bz2 -r-xr-xr-x 1 leonidm 4294967295 1023820093 2012-02-15 15:10 /media/AADK/sources/aadk-1.2.0.tar.bz2 I will switch to my home directory(or any other folder you have write permission to): leonidm@ubuntu:~$ cd leonidm@ubuntu:~$ pwd /home/leonidm Make sure I have at least 4Gb of free space (I have almost 8GB): leonidm@ubuntu:~/aadk-1.2.0$ df -k . Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda1 29640780 20148416 7986676 72% / And will start uncompressing the tar file: leonidm@ubuntu:~$ tar xvfj /media/AADK/sources/aadk-1.2.0.tar.bz2 tar: Record size = 8 blocks aadk-1.2.0/ aadk-1.2.0/external/ aadk-1.2.0/external/neven/ …… 4.2 Configuring the environment To prepare the environment: cd aadk-<version> . build/envsetup.sh lunch Choose the desired platform from the lunch menu: 5. imx51_ccwmx51js-eng 6. imx53_ccwmx53js-eng In my example I will install some missing tools needed for build: leonidm@ubuntu:~$ sudo apt-get install bison flex gperf To prepare the environment: leonidm@ubuntu:~/aadk-1.2.0$ pwd /home/leonidm/aadk-1.2.0 Copyright 2012 Digi International Page 5/13 V1.2 Modifying and re-building Android Kernel and rootfs Modifying and Rebuilding Android Kernel and Root Filesystem leonidm@ubuntu:~/aadk-1.2.0$ . build/envsetup.sh including device/fsl/imx5x/vendorsetup.sh leonidm@ubuntu:~/aadk-1.2.0$ lunch You're building on Linux Lunch menu... pick a combo: 1. generic-eng 2. simulator 3. imx51_bbg-eng 4. imx51_bbg-user 5. imx51_ccwmx51js-eng 6. imx53_ccwmx53js-eng 7. imx53_evk-eng 8. imx53_evk-user 9. imx53_ard-eng 10. imx53_ard-user 11. imx53_smd-eng 12. imx53_smd-user 13. imx50_rdp-eng 14. imx50_rdp-user [I will do this for ccwmx53 so I will choose 6, choose 5 if you use ccwmx51] Which would you like? [generic-eng] 6 ============================================ PLATFORM_VERSION_CODENAME=REL PLATFORM_VERSION=2.3.4 TARGET_PRODUCT=imx53_ccwmx53js TARGET_BUILD_VARIANT=eng TARGET_SIMULATOR=false TARGET_BUILD_TYPE=release TARGET_BUILD_APPS= TARGET_ARCH=arm HOST_ARCH=x86 HOST_OS=linux HOST_BUILD_TYPE=release BUILD_ID=GRJ22 ============================================ Copyright 2012 Digi International Page 6/13 V1.2 Modifying and re-building Android Kernel and rootfs Modifying and Rebuilding Android Kernel and Root Filesystem 4.3 Re-Configuring Android Kernel To make changes to android kernel cd to kernel_imx folder and run following command: make ARCH=arm xconfig in my example: leonidm@ubuntu:~/aadk-1.2.0$ cd kernel_imx/ leonidm@ubuntu:~/aadk-1.2.0/kernel_imx$ pwd /home/leonidm/aadk-1.2.0/kernel_imx leonidm@ubuntu:~/aadk-1.2.0/kernel_imx$ make ARCH=arm xconfig scripts/kconfig/qconf arch/arm/Kconfig Graphical Kernel configuration screen will come up: Copyright 2012 Digi International Page 7/13 V1.2 Modifying and re-building Android Kernel and rootfs Modifying and Rebuilding Android Kernel and Root Filesystem Alternatively depending on your Linux distribution and available packages you can use GTK based GUI (might require sudo apt-get install libgtk2.0-dev libglib2.0-dev libglade2-dev ) make ARCH=arm gconfig Copyright 2012 Digi International Page 8/13 V1.2 Modifying and re-building Android Kernel and rootfs Modifying and Rebuilding Android Kernel and Root Filesystem Or text menu based Kernel configuration tool make ARCH=arm menuconfig This is standard Linux Kernel configuration screen you should be familiar with. Make the changes you need to the Kernel configuration, save and exit the tool. This step will update .config files with the changes you’ve just made in Kernel configuration tool. To see the differences between new .config file created and the default one you can use following command issued from the kernel_imx folder: diff .config arch/arm/configs/imx5_android_ccwmx53js_defconfig To discard your changes and go back to defaults manually delete .config file. 4.4 Modifying root filesystem Whenever a file is modified, the whole root filesystem must be built again to generate new images to boot from FLASH or from NFS. The build process after modifying the root filesystem is much quicker than the first time. Copyright 2012 Digi International Page 9/13 V1.2 Modifying and re-building Android Kernel and rootfs Modifying and Rebuilding Android Kernel and Root Filesystem 4.5 Re-building Android Kernel and rootfs Now the build process can be launched: Go back to the top level of ./ aadk-1.2.0/